Process for producing alpha alumina monohydrate



J. A. AcciARRl l PROCESS FOR PRODUCIVNG ALPHA ALUMINA MONOHYDRATE vFiled Dec. 2, 1964 ATTORNEY United States Patent O 3,419,352 PROCESS FOR PRODUCING ALPHA ALUMINA MONOHYDRATE Jerry Anthony Acciarri and William Charles Ziegenhain, Ponca City, Okla., and Donald L. Ziegler, Denver, Colo., assignors to Continental Oil Company, Ponca City, Okla., a corporation of Delaware Filed Dec. 2, 1964, Ser. No. 415,260 3 Claims. (Cl. 23-143) ABSTRACT OF THE DISCLOSURE Aluminum alkoxide is hydrolyzed with water containing at least 0.25 weight percent ammonia, and a resulting aqueous phase containing alumina is subjected to solvent extraction; better separation vof alumina and alcohol products, and lower product losses result.

This invention relates to a process for producing alumina by hydrolysis of aluminum alkoxide. In one aspect, the invention relates Ito a process for recovering by solvent extraction the alcohol adsorbed on van alphaalumina monohydrate produced by hydrolysis of aluminum alkoxide. In another aspect, the invention relates to a process for hydrolyzing aluminum alkoxide in the presence of a specific amount of a base, and for subsequently removing adsorbed alcohol from the formed alphaalumina monohydrate by solvent extraction. In still another aspect, the invention relates to a process for hydrolyzing aluminum alkoxide in the presence of an aqueous phase and an alcoholic phase, and for recovering alcohol, produced by the hydrolysis, from alpha-alumina rnonohydrate by solvent extraction of the aqueous phase.

Hydrolysis of aluminum alcoholate or alkoxide to produce the corresponding alcohol and an aluminum salt has long been known as a convenient method for preparing alumium salts of high purity. This same hydrolysis process has also been used to produce alcohols, for ex- -ample by hydrolysis of aluminum alcoholates produced in the well-known growth process whereby a low molecular weight aluminum alkyl is reacted with a low molecular weight olen to produce high molecular weight aluminum alkyls.

The actual step of hydrolyzing an aluminum alcoholate has been the subject of considerable study, whether the primary goal be recovery of aluminum salts, alcohols or both. This study has been necessitated by the notorious diiculty of producing aluminum compounds, especially the oxide or hydroxide, of a consistent quali-ty and amenability to separation from the hydrolysis medium. For example U.S. Patent 2,636,865 to Kimberlin, issued Apr. 28, 1953, discloses a process for producing alumina-containing products which comprises introducing aluminum metal and substantially water-insoluble anhydrous alcohol and petroleum distillate into a reaction zone to react the metal and alcohol and form a solution of an aluminum alcoholate, removing the aluminum alcoholate solution from said reaction zone and mixing it with an excess of water to hydrolyze the aluminum alcoholate to form a slurry of hydrous alumina and alcohol, passing the hydrolyzed mixture to a separating zone to allow water insoluble alcohol and petroleum distillate to separate as a layer separate from the water slurry of the hydrous alumina, recovering alumina from the slurry of hydrous alumina, withdrawing separated water insoluble `alcohol and petroleum distillate and drying it to remove water and recycling the dried alcohol and petroleum distillate to said reaction zone for reaction of the alcohol with an additional amount of aluminum. U.S. Patent 2,917,365 to Gilbert, issued Dec. 15, 1959, discloses the method of preparing alumina especially adapted for use as a catalyst support and consisting substantially completely of eta alumina, which comprises the steps of hydrolyzing an aluminum alcoholate solution in water containing `about 0.1 .to 1.0 weight percent of beta alumina trihydrate, at temperatures of from 40 F. to 200 F., the amount of water being in the range of 1 to l0 volumes pe-r volume of -alcoholate solution, agitating the resultant mixture for about 30 minutes, without substantial aging, separating the beta alumina trihydrate slurry formed, drying and heating the alumina to a temperature in the range of 250-1250 F. to further dehydrate it. U.S. Patent 2,970,892 to Kirshenbaum et al., issued Feb. 7, 1961, discloses the method of preparing alumina especially adapted for use as a catalyst support `which comprises preparing a solution of an aluminum alcoholate in a liquid hydrocarbon solvent, slowly adding said solution of aluminum alcoholate to an aqueous solution of ammoni-a containing about 1.8 to 3.4 wt. percent NH3 while vigorously stirring said aqueous solution, the amount of aqueous ammonia utilized being in the range of about l to 10 volumes pe-r volume of alcoholate and the temperature of said aqueous ammonia being in the range of 50 to 200 F., aging the hydrous alumina slurry in the resultant aqueous layer at a temperature below about 80 F. for periods of from one hour t-o live days to convert the hydrous alumina to beta alumina trihydrate, said aging time being near one hour when hydrolysis is effected at temperatures in the lower part of the temperature range and the aging time being about four to five days when hydrolysis is effected at temperatures in the upper part of said range, separating the hydrous alumina from the ex- -cess water and drying to remove the ammonia and aqueous medium, and thereafter heating the hydrous alumina to a temperature in the range of 400-l400 F. to dehydrate it to an adsorptive alumina which is predominantly in the eta phase and which contains more than 40% -of its total pore volume in macropores or pores with diameters between 0.05 and 1.0 micron. Among the problems in the hydrolysis process are: inability to consistently produce, on a commercial scale, the desired structural type of alumina; difficulty in recovering alcohols adsorbed or absorbed by the alumina; and poo-r filtration rates due to alumina oc formation.

Accordingly, it is an object of this invention to provide a process -for hydrolyzing aluminum alcoholates wherein carry-over of alumina in the alcohol product stream is substantially reduced, producing purer alcohol with lower alumina losses.

It is another object of the invention to provide an aluminum alcoholate hydrolysis process wherein alphaalumina monohydrate can be consistently produced.

It is a further object of this invention to provide an aluminum alkoxide hydrolysis process wherein the produced alumina is amenable to ready separation from the hydrolysis medium.

Other aspects, objects and the several advantages of this invention will become apparent upon study of this disclosure, including the appended claims and the drawing, in which the sole figure is a schematic representation of a presently preferred embodiment of this invention.

According to the invention, aluminum alkoxides are hydrolyzed by being introduced into a reaction zone along with water and a controlled minor lamount of ammonia, the ratio of alkoxide to water being such as to maintain two liquid phases. The resultant slurry of alumina, alcohol and water is then subjected to countercurrent extraction and settling phase separation with a lower alcohol extraction medium. In one embodiment of the invention, the extraction of the aqueous hydrolysate phase is effected in at least two contacting stages with intermediate and iinal phase separation of the aqueous raffinate and alcoholic extract phases.

Reference is now made to the drawing for a more complete understanding of the invention. Alkoxide feed stream 1 can advantageously comprise an oxiis withdrawn by way of conduit 19, and can be suitably dried and/ or calcined for the desired end use. Aqueous medium is withdrawn by way of conduit 20, and can be recycled to hydrolysis reactor 5. Requisite heaters, coolers, pumps, valves, etc., are not shown.

dized growth product, the preparation of which 1s The invention will be further illustrated by the followdescribed, for example, in U.S. Patent 3,070,616 to ing examples. Flanagan, issued Dec. 25, 1962. Other sources of EXAMPLE 1 alummum aufoxfde are of COrse slmable' Wziter In this example, hydrolysis and extraction were effected Preferably delomzefi for hydrolysls 1S lmroduced mto 10 in the same vessel, which comprised a vertical 6-inch di- ;eactor 51 a1onfe-w11th the alkxlde feefi- Wate strcagn ameter pipe 29.5 feet high. This apparatus was not that Contms a CFUSCaTmOUIt ammoma mtrozufe y shown in the figure. Alkoxide feed and water were intro- Wall Condult e. fano s teaflls 1 F0 1S COI; duced in a zone from l5 to 49 inches from the top; this tro e S0 as todmafftmhtll? lgull P 3561s 1g rleactor zone comprised the reaction section, and was agitated and n aquleogls an a. 30 0 IC- H b @l/er E bcod 0 such as l" baied as footnoted on the runs. The pipe volume below H3110 fom @Xlactlnlw e esc@ e enters fe' the reactor section was an extraction zone by virtue of aCOf'S by Way 0 con 1t eac/[9F 5 1 5 equlPPed Wlth ethanol solvent being introduced near the bottom of the agitation means such as a motor driven impeller and/or pipe- A slurry of alumina in extraction medium was with- Propellers-Alcohol PfQdUCt from hydrolysis, along Wflh drawn from the bottom, and product alcohol plus extracthe extraction HlCOhOL 1S YCITIOVCf fl'Om the UPPET POUOU 2O tion ethanol was withdrawn from the top. The ratio of 0f th@ reactor by Way 0f COHdUl 4- A Slwffy COIUPllSmg water to alkoxide to solvent was varied to demonstrate the alumina With occluded alCOhOl 1H Water 1S WithdraWIl by dependence of alumina loss in overhead alcohol product way of conduit 6, mixed with extraction medium to be on feed ratio. In runs 4-15, there were maintained two later described via conduit 7, and introduced into a first liquid phases, an aqueous and an alcoholic, with the aluextraction zone 8. Extractor 8 contents are preferably mina being removed from the bottom of the extraction vigorously agitated. A slurry of alumina, water and exzone as an aqueous slurry. In runs -49, there was prestraction medium is withdrawn from extractor 8 and passed ent only a single liquid phase, alcoholic, with alumina by way of conduit 9 to a rst phase separator 10, which product being removed as aslurry in alcohol.

TABLE 1 A Percent Alkoxide Weight Ratios Temperatures, F. 3 Run Feed Rate, Agitator, Solvent i Loss l in Footnote Number Lb.,/Hr. r.p.1n. Water Alkoxide Solvent Alkoxide Reaction Extraction Alcohol Remarks Feed Section Section Product so. 0 120 o. 914 i. 00 0. 832 B 145 140 14o 1. 16 (i) 67. 0 70 0. 850 1. 00 1. 025 B 140 140 150 o. 44 5) o1. o 70 1. 03o 1.00 1. 192 B 212 210 222 1. 13 59. o o4 esi 1. oo 0. 954 B 212 20o 20o c. 75 51 o2. o 0.7911 1. co o. eco B 212 205 19o 0. 2s o) 61. o 175 0. 657 1. o0 0. 989 A 14o 15s 13s o. 37 (s) 60. 0 25-30 o. 309 1. oo o 989 A 14o 175 165 70.1 ,3) 51. 1 40 o. 307 1. oo o. 46s A 137 150 15o 54. 7 21 52. s so 0.453 1. 0o 106s A 165 175 15o 27. 1 (4') 63. 5 193 o. 639 1. 0o 1. 172 A 170 17o 155 4s. 1 (4) 49. t) 0. 573 1. 00 1. 191 B 190 180 160 17. 2 (4) 49, o 1. 00 1. 191 B 19o 180 15o 46. i (4) 55. o 1. 0o 0. 858 B 195 190 160 37. o (i) 57, 0 1.00 1. 400 A 160 157 153 42. 4 u) 27, 0 1. 0o 3. 200 A 160 150 145 20. s (i) 49, 6 1. 00 1. 592 A 164 187 17o 2. s4 (i) 43, 1 1. 0o 1. 825 B 162 165 140 4. o2 (a) 43, g 1.00 2. 047 B 15o 155 14o 14. 3 (a) 45, 5 1.00 2. 191 A 155 170 155 3. 0o o) 5s. 9 1.00 1.975 A 165 172 140 s. 27 (2) 1 Percent of total alumina produced in hydrolysis that goes out with the alcohol product` 2 A=93.8 Weight percent ethanol, 6.2 weight percent Water. B =84.1 weight percent ethanol, 11.1 weight percent methanol, 4.8 weight percent water.

is maintained quiescent. The alcohol phase, which coniprises extraction medium plus product alcohol formerly occluded on the alumina, is withdrawn from an upper region of settler 10 and passed by way of conduit 11 to the hydrolysis reactor. An aqueous slurry of alumina with small amounts of alcohol is withdrawn from a lower region of settler 10 and passed by way of conduit 12 into admixture With feed extraction medium from conduit 13. Although not shown, it is obvious that alcohol product stream 4 can be fractionated to recover extraction medium for recycle to conduit 13. The thus-admixed stream of fresh extraction medium and alumina in water is introduced into a second extractor vessel 14, similar to vessel 8, and also preferably vigorously agitated. The material is passed by way of conduit 15 to a second phase separator 16, similar to 10. Extraction medium plus recovered alcohol is withdrawn from an upper portion by way of conduit 7 and recycled to irst extractor 8. A sluriy of alumina in water is withdrawn from a lower region by way of conduit 17 and passed to a separation means 18, such as a filter. Pured and separated alumina product 3 The reaction section contained paddle agitators over the screens Screen openings varied from 2.5 to 11.0 111m.

4 The reaction section contained two opposing turbine agitators with aluminum alkoxide and water being fed bet-Ween them.

5 The reaction section contained paddle agitators but no screens.

It can be seen from the preceding runs that operation with the reaction zone containing a single liquid alcoholic phase in runs 30-49 resulted in high losses of alumina carried overhead in the alcohol product. In such an instance, valuable alumina product is lost, and when the alcohol product is subjected to any subsequent heating such as distillation, the alumina contaminant catalyzes dehydration of the alcohols to oleiins and also causes fouling of heat transfer surfaces. In contrast, control of feed ratios to maintain two liquid phases, aqueous and alcoholic (runs 4-15) substantially reduces carry-over, since the alumina prefers the aqueous phase.

EXAMPLE 2 Additional runs were made in the apparatus of Example l in which the extraction zone was operated first as an aqueous phase saturated with n-butanol extraction medium (runs 18-20) and then as an n-butanol phase saturated with Water (runs 21-22). From these runs it can be seen that loss of alcohol by occlusion on alumina product is lower in the first than the second instance.

TABLE 2 .Alkoxide Weight Ratios Temperatures, F. Percent Run Feed Rate, Alcohol Number Lb./Hr. Water .Alkoxide n-Butanol Alkoxlde Reaction Extraction Recoveryl Feed Zone Zone 1 Percent of total alcohols formed in reaction zone that are recovered as product alcohol in overflow stream from clarification zone.

This indicates that the interface between the aqueous and the alcohol phases should be maintained above, rather than below, the extraction section, since the alumina fed into the extraction section from hydrolysis apparently does not readily pass the alcohol-water interface.

The following examples illustrate the effect of hydrolysis water pH upon the recovery of alumina and alcohols and the filterability of the alumina. These runs were made in the apparatus of the figure.

EXAMPLE 3 This run was made with acidic deionized water feed (pH=3.35) such that the aqueous alumina slurry leaving the hydrolysis reactor was also -acidic (pH=6.1). The process was completely inoperable and filtration of the alumina slurry was impossible.

EXAMPLE 4 This run was made using neutral (pH- .-7.0) deionized feed water. Under these conditions, the aqueous alumina slurry leaving the hydrolysis reactor was basic (pH=7.8). The maximum filtration rate possible on the rotary vacuum drum filter was 35 pounds filter cake per hour per square foot filtering area. Because of the butanol-wateralumina emulsions formed in the extractors, product alcohol recovery was very low (98.56%). The presence of this emulsion makes operation of the phase separators very difficult. Upon recycling the filtrate to the hydrolysis reactor, this same emulsion causes thickening of the alumina slurry, causing a shutdown in the process.

EXAMPLE 5 This run was similar to Example No. 4 but with the addition of 0.125 weight percent ammonia to the fresh deionized water feed. The filtration rates were not improved over Example No. 4. The emulsions between butanol-water-alumina were again present but not as bad as the emulsions present in Example No. 4. The `alcohol of lesser emulsification. Recycle of the `filtrate, however, to the hydrolysis reactor caused the same shutdown problems explained in Example 4.

EXAMPLE 6 This run used 0.25 weight percent ammonia in -the fresh deionized feed water. With this addition, all emulsification problems disappeared, filtration rates increased to pounds filter cake per hour per square foot filtering area, and alcohol recovery increased to 99.65 percent or greater. Recycle of filtrate (no emulsion now presen-t) to the hydrolysis reactor caused no operational problems whatsoever.

EXAMPLE 7 EXAMPLE 8 This run was similar to Example No. 6, but with 0.375 weight percent ammonia added to the fresh deionized water feed to the hydrolysis reactor. Adding this excess ammonia (excess over 0.25 weight percent) neither aided nor harmed the process operations.

It can -be seen from the preceding Examples 3-8 that the hydrolysis water feed pH is critical to proper operation of the process, and that this water preferably is deionized and then has added toit at least about 0.25 weight percent ammonia.

The following table summarizes the conditions prevailrecovery was improved (99.59%) Over Example 4 because 50 mg during Examples 3-8.

TABLE 3 Example Number 3 4 5 6 7 8 Aluminum Alkoxides Feed Rate, 1b./hr. (l) 150 150 150 150 150 150 Weight Ratio:

Feed Water (2) /alkOXlde (1) 1. 5 1. 42 1. 72 1. 5 1, 5 1. 5

Butanol (13) /alkoxide (1) 0. 67 0. 67 0. 67 0` 67 0. 67 0. 67 Temperatures, F.:

Hydrolysis Reactor (5) 220 225 240 225 234 234 1st Extractor 200 220 224 210 225 225 1st Phase Separator (10) 200 220 224 210 210 210 2nd Extractor (14) 195 210 218 205 210 210 2nd Phase Separator 195 210 218 205 205 205 Filter (18) 185 150 165 160 140 140 Pressures:

Hydrolysis Reactor (5), p.s.i.g 60 58 60 47 49 50 1st Extractor (8), p.s.i.g 30 38 30 25 32 20 1st Phase Separator (10), p.s.l.g 28 36 28 25 31 20 2nd Extractor (14), p.s.l.g 25 33 24 20 22 15 2nd Phase Separator (16), p.s.i.g 23 31 20 19 21 14 Filter (18):

Cake Forming, in. Hg 13 2O 13 15 15 13 Cake Drying, in. Hg 8 15 8 10 10 10 Weight Percent A1203 in.-

lochols (4) 0.01 0.003 0.02 0.02 0.01

Filter Cake (19) 13. 4 14.7 14. 7 14.4 15.1

Filtrate Recycle (20) 0.18 0.08 0. 09 0.09 0. 26 Lbs. NH3 (3) /100 lbs. Feed Water (2) 0 0 0.125 0. 25 0. 25 0.375 pH Feed Water (2) 3. 35 7.0 11.0 11.1 11.1 11.2 pH Slurry to Filter (17) 6.1 7.8 10. 2 10.2 10.2 10.5 pH Filtrate (20) 7. 8 9.8 10. 4 10. 2 10. 25 Filtration Rate, 1b. cake/(hr. x it?) 0 30-35 30-35 50-60 50-60 50-60 Percent Ultimate Alcohol Recovery- 98. 56 99. 59 99. 65 99. 77 99. 77 Emulsification of Butanol-Water Slurr No Yes Partial No No No The following example is a material balance on the process of .the figure.

EXAMPLE 9 Material Balance Basis: 100 lbs. alkoxide.

8 133 micron mesh filter cloth, filtration rates of at least about 50 1b. cake/hr.ft.2 can be obtained.

Although ethanol and butanol have been the main extraction solvents discussed, it is obvious that other solvents will function. It has been found that the type of Hydrolysis Temperature: 230 F. 5 solvent used for extraction has an effect upon the physical Hydrolysis Pressure: 60 p.s.i.a. nature of the alumina product, i.e., alumina from an etha- Hydrolysis Rate: 437.5 lb. alkoxide per hr. per ft2. no1 extraction appears to be slightly more filterable than Filtration Rate: 39.5 lb. filter cake per hr. per ft2 does that from a butanol extraction. The use of n-butanol (filter not loaded). is presently preferred because it is available by fractiona- Filtration Unit: Dorf-Oliver 1 ft. X 1 ft. rotary vacuum tion of the product alcohol stream, it has a relatively low filter. solubility in water, and it yields a readily filterable alu- Filter Cloth: 133 Micron opening monolilament polymina. However, other extraction media such as esters, propylene. ethers, aldehydes, ketones and paraflins, all of low molec- Filtration Temperature: 180 F. 15 ular weight, can be used. When using a solvent type other Filtration Vacuum: 13 in. Hg. than an alcohol, separation of the solvent from the alcohol Percent Component Alk- Alcohol Total of Theooxide, Wate Butanol, Prod Alumina, Wt., retical Stream lb. lb. 1b. lb. lb. 1b. Alcohol Number Name Product ost (i) Allrexide Feed 100.00 (2)-.- Water Feed 1 89.5 (4).--

Alcohol Product.-- 16.8 50.12 89.05 0.03 (6) Reactor Slurry. 12S. 67 8. 51 5. 0 11.92 (7) Recycle Butaiio1 20. 4 49. 24 1. 45 0.01 (9) urr 14s. 07 57. 75 6.45 11.93 (11) Recycle Butanol. 17. 8 51.14 4. 75 0.01 (i2) Decanter slurry 131. 27 is. 6i 1. 70 11. 92 (i3) Butaiio1Feed 64.5 (15) slurry 131.27 71.11 1.70 11.92 (i7) Decanter slurry.-- 110. 87 21.87 0.25 11.91 (i9) Filter Cake 50.7 0.87 0. 25 11.78 Reeyele Filtrate.. 44. 37 3.0 0.13

Filtrate Loss 6.8 9.0

1 Includes 0.25 lb. N H3 per 100 lb. deionized H2O.

Preferred hydrolysis reaction conditions are about 200 product can present a problem. The two requisites of the to about 330 F., more preferably about 230 F., with 40 solvent are that it be selective to alcohols in the presence pressure sufficient to maintain liquid phase. Pressure will, of water, and that it is capable of forming two liquid of course, vary with the type of extraction solvent used phases, a solvent-rich phase and a water-rich phase. Other and with reaction temperature; for n-butanol solvent at solvents include methanol, n-hexanol, i-propanol, t-butzi the preferred temperature, about 60 p.s.i.g. pressure sufno1, dimethylsulfoxide, acetone, methylisobutyl ketone, difices. When operating according to the specified reaction ethyl ether, acetaldchyde, n-pentane and ethyl acetate. conditions, the alumina has been shown to be consistently As mentioned, suitable alkoxide feed includes oxidized essentially entirely alpha-alumina monohydratc. Other growth product. Such material normally comprises tripreferred process conditions include ratio of water to alkoxy aluminum iii which the alkyl groups range in caralkoxide feed, preferably about 1.0` to 3.0 pounds per bon content from 2 to about 30 each. In the event of some pound, more preferably about 1.4 pounds per pound. diluent being present with the oxidized growth product Residence time in the hydrolysis reactor appears to have from its prior processing, the diluent is preferably first little effect on the process, but is preferably at least about stripped from the alkoxides in order that it does not inter- 1 minute. Extraction temperature and pressure will defere with the present extractions. Other sources of alumipend upon the extraction solvent being used; in the case of num alkoxides are, of course, amenable to treatment by buantol, best extraction efficiency is obtained between the process of this invention. about and 230 F., preferably about 200 F., at a pres- While particular embodiments of the invention have sure about 15 and 30 p.s.i.g., preferably about. 20 p.s.i.g. been described, it will be understood, of course, that the Extraction Zone residence time Will dfpel'ld 111 .a large invention is not limited thereto, since many modifications degree uP011 design 0f fh? Zone, llcludlng agltatlof em' may be made; and it is, therefore, contemplated to cover Celcy, but Preferably Wlu be at ea'st about 2 mlIlUe/Si 60 by the appended claims any such modifications as fall more Preferably at least fflbolft 4 minutes-.The ratio Pf within the true spirit and scope ofthe invention. extraction solvent to alumina in the extraction zones will What is Claimed is. also depend upon the type of solvent used; in the case of 1. In a process for preparing alpha alumina m0nohy butanol, the ratio is preferably at least about 2.0 on a drate wherein Weight basis and more Preferably at least about 4'8' .Con- 65 (a) a stream containing aluminum alkoxide, each alkditions in the phase separator can be readily determined, oxide radical Containin from 2 to about 30 carbon and will depend upon physical configuration. Operable t d t g t. conditions of temperature, pressure and residence time are a oms 1S pass@ o a reac on Zone about 180 220s F. preferably about 200 F, about 13 28 (b.) a stream of waterin amount sufficient to maintain p.s.i.g., preferably about 18 p.s.i.g., and about 3-50 min- 70 m Sad Zone two hquld Phases a Water'rlch Pilase and ari alcohol-rich phase, is also passed to said reaction zone; (c) there is withdrawn from an upper region of said Zone a product comprising said alcohol-rich phase; (d) there is withdrawn from a lower region of said zone 9 10 said water-rich phase now containing solid alpha alu- References Cited mina monohydfafe? UNITED STATES PATENTS (e) said Water-rich phase is contacted with a solvent,

selective for product alcohol and capable of forming 2,636,865 4/1953 Kfmberlm,

a non-aqueous phase in the presence of water, in pro- 5 2,805,920 9/1957 Rlchardson 23*"143 portion to form two liquid phases; 2,903,418 `9/ 1959 Kirshenbaum et al. 23-143 X (f) there is withdrawn from said contacting an alcohol- 2,917,365 12/1959 Gllbert 23-143 enriched Solvent phase; 2,970,892 2/ 1961 K rrshenbaum et al.

(g) there is also withdrawn from said contacting a 3,019,080 1/1962 Vl'nnt 23-'143 Water-rich phase containing alpha alumina monohy- 10 3,255,256 6/1966 Miner 260*448 X drate; and 3,264,063 8/1966 Carter 23-143 the improvement comprising incorporating in said Water of step (b) from about 0.25 to 10.375 weight percent am- 15 EARL C' THOMAS Primary Examiner' momia. G. T. OZAKI, Assistant Examiner.

2. The process of claim 1 wherein said solvent comprises an alcohol of up to about 6 carbon atoms. U-S Cl- X-R- 3. The process of claim 2 wherein said solvent com- 26o-448 prises n-butanol. 20 

